3D-Patterned Fiber Web Drying for Higher CD Extensibility

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing methods for improving the extensibility of fiber webs, such as paper or board products, primarily focus on machine direction (MD) and do not significantly enhance cross-machine direction (CD) extensibility, limiting their potential in applications like packaging where high extensibility is crucial.

Innovation Solution

A method involving the imposition of a three-dimensional pattern on a wet fiber web, allowing it to shrink under low restraint during evaporative drying, which increases both MD and CD extensibility through enhanced drying shrinkage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If in-plane compaction is applied using technologies like Expanda or Clupak, then machine direction (MD) extensibility is improved, but cross-machine direction (CD) extensibility remains unchanged

Engineering Contradiction:

ImproveMD extensibilityVSAvoidCD extensibility

Core Design Contradiction:

Length of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent applies a three-dimensional pattern (corrugations, crepes, or embossed patterns) to the fiber web, introducing a new dimensional structure that enables CD extensibility without compromising MD extensibility. This dimensional transformation allows the material to expand in multiple directions, resolving the contradiction between MD and CD extensibility improvement

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces curved or wavy patterns (corrugations and crepes) into the fiber web structure. These curved geometries provide mechanical compliance that enables expansion in both MD and CD directions, overcoming the limitation of flat, rigid structures that only allow expansion in one direction

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Adaptability or versatility

If the web is contracted using bowed Mont Hope type rolls, then CD extensibility is improved, but MD extensibility remains unchanged

Engineering Contradiction:

ImproveCD extensibilityVSAvoidMD extensibility

Core Design Contradiction:

Adaptability or versatilityVSLength of moving object

Solution Approach 1:

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The three-dimensional pattern structure serves multiple functions simultaneously: it provides CD extensibility through the pattern geometry, maintains MD extensibility through proper pattern orientation and spacing, and enables controlled drying shrinkage. This multi-functionality resolves the contradiction by making the structure universally beneficial for both directions

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If a three-dimensional pattern is imposed on a wet fiber web, then both MD and CD extensibility are improved through enhanced drying shrinkage, but the process complexity increases

Engineering Contradiction:

Improveextensibility in both MD and CDVSAvoidpattern imposition process

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent utilizes the porous, wet state of the fiber web during pattern imposition, allowing the pattern to be easily formed through compression or embossing. The porous structure enables the web to conform to the pattern and then shrink during drying, achieving extensibility improvement without requiring complex equipment

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent exploits the change in physical parameters of the fiber web during the drying process. The web transitions from a wet, compliant state (easy to pattern) to a dry, rigid state (maintains pattern and provides extensibility). This parameter change enables simple pattern imposition to achieve complex functional outcomes

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method results in fiber products with improved extensibility, particularly in the CD direction, enhancing their potential to replace plastics in packaging applications.

Implementation Method 1

allowing the web to shrink under low restraint during evaporative drying

Methodology Applied

Scientific EffectEvaporative drying: Evaporation

Implementation Method 2

the imposed pattern together with the achieved increased drying shrinkage cause an improved extensibility

Methodology Applied

Scientific EffectDrying shrinkage: Thermal Contraction

Data Source

PatentUS20250347057A1Boosting the cross-machine direction shrinkage and extensibility of a fiber product

Publication Date: 2025.11.13 TEKNOLOGIAN TUTKIMUSKESKUS VTT OY

AI summary

The present invention concerns a method for modifying a fiber network of a fiber web, typically made of a cellulose-based pulp, in order to increase the drying shrinkage as well as boost the cross-machine direction (CD) extensibility of the thus prepared fiber product. The method includes the steps of imposing a three-dimensional pattern in the wet fiber web, and drying the web using evaporative drying while allowing the web to shrink without major restraints. The pattern is imposed on the web in the forming section or after the forming section, before evaporative drying, while utilizing the wet elongation of the web for the shapes of the pattern, thereby not affecting the width of the wet web. The invention also concerns the formed fiber product having an increased CD extensibility.